Karelo-Finnish SSR

The Karelo-Finnish Soviet Socialist Republic was a republic of the Soviet Union that existed from 1940 to 1956, with Petrozavodsk serving as its capital. The republic was established on 31 March 1940 as a merger of the Karelian ASSR and the Soviet-occupied parts of eastern Finland, and all 422,000 Karelians from the ceded areas were evacuated to Finland and replaced by settlers from other parts of the USSR. In the ensuing Continuation War, Finland re-annexed the lands that had been ceded to the USSR, only for the USSR to reconquer these areas in 1944. In 1956, the republic was incorporated into the Russian SFSR as the revived Karelian ASSR.